1. Field of the Invention
The present invention relates to the field of portable computer systems, such as personal digital assistants or palmtop computer systems. Specifically, embodiments of the present invention relate to a portable computer system equipped with a dielectric elastomer actuator (e.g., an electronic muscle material) for sensing certain actions for entering and exiting power modes and for modifying a display.
2. Related Art
A portable computer system, such as a personal digital assistant (PDA) or palmtop, is an electronic device that is small enough to be held in the hand of a user and is thus “palm-sized.” By virtue of their size, portable computer systems are lightweight and so are exceptionally portable and convenient. These portable computer systems are generally contained in a housing constructed of conventional materials such as rigid plastics or metals.
Portable computer systems are generally powered using either rechargeable or disposable batteries. Because of the desire to reduce the size and weight of the portable computer system to the extent practical, smaller batteries are used. Thus, power conservation in portable computer systems is an important consideration in order to reduce the frequency at which the batteries either need to be recharged or replaced. Consequently, the portable computer system is placed into a low power mode (e.g., a sleep mode or deep sleep mode) when it is not actively performing a particular function or operation.
There are many other similar types of intelligent devices (having a processor and a memory, for example) that are sized in the range of laptops and palmtops, but have different capabilities and applications. Video game systems, cell phones, pagers and other such devices are examples of other types of portable or hand-held systems and devices in common use.
These systems, and others like them, have in common some type of screen for displaying images as part of a user interface. Many different kinds of screens can be used, such as liquid crystal displays, and field emission displays or other types of flat screen displays.
These systems also have in common some type of user interface allowing a user to input commands and information and to navigate either within an application or from one application to another. In the case of laptops and some of the other hand-held devices, an optional alphanumeric input device including alphanumeric and function keys (e.g., a keyboard) can be provided. The keyboard can also be used to control a cursor on the display device, or an optional cursor control device (e.g., a mouse, trackball, joystick, stylus, or touchpad) can be used. It is well known how a cursor can be used to select various functions, commands and applications, and how a cursor can be used to navigate within applications.
In the case of palmtops and other such devices, a touch sensor (touchpad) which is able to register contact between the screen and the tip of a stylus element typically covers the display device. The user can input commands and move between applications by touching the stylus to various parts of the screen or to virtual buttons rendered on the screen. Many palmtops are also equipped with a handwriting recognition pad (e.g., a graffiti area, digitizer or digitizer tablet) that can recognize characters traced on the pad by a user. Palmtops and many other hand-held devices also have built-in dedicated or programmable buttons or keys that can be used to implement various functions and to navigate among and within different applications (see FIG. 1.)
Some portable computers contain speakers for audible alarms or for playing recorded messages. Likewise, they may contain microphones for recording information. Some also contain mechanisms that cause the device to vibrate when the audible alarm is turned off.
Thus, there are various well-known mechanisms that are used in the prior art to provide a user interface for hand-held and/or portable computer systems and the like, including laptops and palmtops. These mechanisms tend to work well with the different types of display devices and other mechanisms currently in use.
However, the paradigm of applying conventional user interface mechanisms to hand-held, portable devices does not take full advantage of the user's capability to control and manipulate such devices. The automatic deep sleep mode, even though somewhat effective for improving battery life, requires a short wait period for awakening. Also, the deep sleep mode only activates after a certain designated period of idle time has elapsed. Thus, it is desirable to provide a more efficient method of entering and exiting the power mode. An improved interface can facilitate the user's experience compared to other devices that employ conventional user interfaces.
A material called a dielectric elastomer has recently been introduced by Ron Pelrine, et. al. of SRI International. Information on this material is published in Proceedings of SPIE Vol. 4329 (Electroactive Polymer Actuators and Devices, 2001) from Smart Structures and Materials Symposium 2001, March 4–8, Newport Beach, Calif. This information is hereby incorporated by reference as background material.